. Rain and freezing temperatures ____ to make snow.
| A．combined | B．combine | C．combine with | D．combined with |
The thought of going back home was _______ kept him happy while he was working abroad.
| A．that | B．all that | C．all what | D．which |
Although medical science __________ control over several diseases,what worries us is that some of them are returning.
| A．achieved | B．has achieved | C．will achieve | D．had achieved |
---What happened to the house ?
---It_____burnt to the ground.
A is said to having been B. is supposed to have been
C is reported to have been D. is believed to have
---You must obey every word of mine!
---_______ I don’t?
| A．How if | B．What if | C．Even if | D．Only if |
How long do you think it will be _______ China sends another manned spaceship to the moon?
| A．when | B．until | C．that | D．before |